Bok Gwi Joo and his family were born with different supernatural powers. Bok Gwi Joo is able to travel back in time, but only to happy times in his life. He can't change the past, so he can only dwell on those happy moments. Bok Gwi Joo becomes afflicted with depression, and this leads him to lose his supernatural power. His family also loses their own powers due to modern-day problems like insomnia, bulimia, and smartphone addiction. One day, Do Da He happens to get involved with Bok Gwi Joo and his family. She begins to live with them, and change occurs. (Source: AsianWiki)